Due to their composition, many cosmetic products are susceptible to act as a culture medium for microorganisms, and this can cause possible alterations to the cosmetic preparation and constitute a possible risk to human heath as well. Thus, a cosmetic composition requires good protection against microbiological contamination.
A well-known substance used for the protection against microorganisms is a cationic surfactant derived from lauric acid and arginine, in particular, the ethyl ester of the lauramide of the arginine monohydrochloride, hereafter named LAE. The chemical structure is described in the following formula:

This compound is remarkable for its activity against different microorganisms, such as bacteria, fungi and yeasts and its use is known in food and feed preparations. The compound is well-known to be harmless to animals and humans. The minimum inhibitory concentrations of LAE are shown in the following table 1.
TABLE 1M.I.C. KindMicroorganism(ppm)Gram + BacteriaArthrobacter oxydans ATCC 801064Bacillus cereus var mycoide ATCC 1177832Bacillus subtilis ATCC 663316Clostridium perfringens ATCC 7745416Listeria monocytogenes ATCC 764410Staphylococcus aureus ATCC 653832Micrococcus luteus ATCC 9631128Lactobacillus delbrueckii ssp lactis CECT 37216Leuconostoc mesenteroides CETC 91232Gram − BacteriaAlcaligenes faecalis ATCC 875064Bordetella bronchiseptica ATCC 4617128Citrobacter freundii ATCC 2263664Enterobacter aerogenes CECT 68932Escherichia coli ATCC 873932Escherichia coli 0157H720Klebsiella pneumoniae var pneumoniae32CECT 178Proteus mirabilis CECT 17032Pseudomonas aeruginosa ATCC 902764Salmonella typhimurium ATCC 1602832Serratia marcenses CECT 27432Mycobacterium phlei ATCC 414232FungiAspergillus niger ATCC 1460432Aureobasidium pullulans ATCC 934816Gliocadium virens ATCC 464532Chaetonium globosum ATCC 620516Penicillium chrysogenum CECT 2802128Penicillium funiculosum CECT 291416YeastCandida albicans ATCC 1023116Rhodotorula rubra CECT 115816Saccharomyces cerevisiae ATCC 976332